REACTIONS TO LIGHT AND GRAVITY IN DROSOPHILA 67 
the indices of the individuals constituting the group. It is the 
indices thus obtained that are set down in table 8. From these 
results it would appear that there is a slight recovery of photo- 
tropism. Nevertheless, in view of what occurs in normal flies 
TABLE 8! 
DAYS 
GROUP 1 2 3 4 5 
tl. fie tle fl. ll: fl. tl. fl. tl. fl. 
Tey in te see 3 24.0 17.6 So 8.6 4.3 
JUL). Mee tek ee ee ee 00.7 15},.83 12.8 2.0 Dee 
TELE Pas ea tN Oe 10.0 8.9 3 18.5 9.9 
Vite boy ikryard-ns Ay 1.@ 00.7 00.9 3.0 
Vai a 2 hwy) ieee 00.4 00.3 2.0 \ 4.7 0.4 
otal See eee 00.7| 38.7 43 1). 42.1 PAAD Bp 7 19.9 
Average........ 00.7} 9.6 8.6 8.4 2 OR Set 3.9 
Differences..... 8.9 8.6 8.4 6.1 3.9 
DAYS 
GROUP 6 7 8 9 10 
tle fl. tl. fl. tl. fl. tl. fl. tle fl. 
DiS ee lid 4 io (0 15.0 18.4 10.0 
NW eres, Sere 10.3 3.6 16.0 4.3 137 
Tig Soe See 3.9 4-2 145 Qe Sal 00.7 
VERE eet 10.3 2.9 Bei 4.1 18.6 
Ve ee 4.4 ee 4.3 Sno) 
Rotalsiee eee 24.5) 6.1 10.6) yas) |) eel) |) TA || etssec) 423) || 00.7 
Average........ eles seal 2.9) | ION eae de 14.1 | 00.7 
Differences.....}| 5.1 2.4 4.0 Hall 13.4 
' No temperature was taken in these early experiments, but later tests made 
in the same room under similar conditions showed a variation of less than a 
degree during a period of two weeks. 
tl. indicates excess of inches crawled toward light, resulting from the alge- 
braic sum of indices in the group. fl. indicates excess of inches crawled away 
from the light, calculated in the same manner. Diff’s. indicates the algebraic 
sum of the fl and tl averages. 
